66799986 has 48 divisors (see below), whose sum is σ = 148466304. Its totient is φ = 20020000.

The previous prime is 66799979. The next prime is 66800003. The reversal of 66799986 is 68999766.

It is a happy number.

It is a super-3 number, since 3×66799986³ (a number of 24 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 72871 + ... + 73781.

It is an arithmetic number, because the mean of its divisors is an integer number (3093048).

Almost surely, 2^66799986 is an apocalyptic number.

66799986 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 66799986, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (74233152).

66799986 is an abundant number, since it is smaller than the sum of its proper divisors (81666318).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66799986 is a wasteful number, since it uses less digits than its factorization.

66799986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1039 (or 1028 counting only the distinct ones).

The product of its digits is 8817984, while the sum is 60.

The square root of 66799986 is about 8173.1258402156. The cubic root of 66799986 is about 405.7502447677.

The spelling of 66799986 in words is "sixty-six million, seven hundred ninety-nine thousand, nine hundred eighty-six".